Wow I had not seen this thread before.
I believe those fabric grow pots were intended to be used in conjunction with a self-watering tray/platform. At leat that's the way they were sold when they first started showing up in gardening catalogs. You could buy them or make your own. Have you seen the home-made self watering seed starting tray
that was posted in the recycled container thread in Seed Strating Forum? It's that kind of design..
I think you could make one with an under-the-bed kind of shallow storage container, largish table busing tub used in restaurants, or maybe concrete mixing tub. I'm thinking carpet felt for wicking mat. I'll let you come up with the riser and platform.
I think if I were trying one of those grow bags/pots, I would put it directly on the (dirt/grassy) ground. That way, as long as there are no drought conditions moisture could be wicked up from the ground.